4.Plate Tectonic Theory & Continental Drift Theory

Question 1

What is a destructive plate margin?

Answer 1

A destructive plate margin is a boundary where two tectonic plates move towards each other, and one plate is forced beneath the other into the Earth’s mantle.

Question 2

What happens when a continental and an oceanic plate collide at a destructive margin?

Answer 2

When a continental and an oceanic plate collide at a destructive margin, it can lead to the formation of Fold Mountains, Volcanic Eruptions, Trenches, and Earthquakes.

Question 3

How are Fold Mountains formed at a destructive margin?

Answer 3

When two plates are pushed together at a destructive margin, compression force is created, leading to the warping of rocks which eventually creates Fold Mountains.

Question 4

What is a volcanic eruption, and how is it formed at a destructive margin?

Answer 4

A volcanic eruption is the ejection of material (such as lava, ash, and gas) from a volcano. At a destructive margin, when a dense plate subducts, the rocks of the subducting plate get into contact with magma beneath the earth’s surface. The pressure under the magma chamber pushes magma upward, leading to volcanic eruptions.

Question 5

What are Trenches, and where do they get created at a destructive margin?

Answer 5

Trenches are the deeps that get created between oceanic-continental destructive boundaries. They get created at a destructive margin when one plate is forced beneath another.

Question 6

What are the different reasons for the formation of an earthquake at a destructive margin?

Answer 6

The different reasons for the formation of an earthquake at a destructive margin are:

Friction between the two plates during subduction.
Faulting of plates due to collision.
Compression of plates due to collision.

Question 7

What is the Beni-Off Zone?

Answer 7

The Beni-Off Zone is the place or spot where earthquakes occur at a destructive margin.

Question 8

What is the Beni-Off Zone?

Answer 8

The Beni-Off Zone is the place or spot where earthquakes occur at a destructive margin.

Question 9

What are the features that can be seen at a continental-oceanic plate collision?

Answer 9

The features that can be seen at a continental-oceanic plate collision are Fold Mountains, Volcanic Eruptions, Trenches, and Earthquakes.

Question 10

What are some examples of a continental-oceanic plate collision?

Answer 10

Some examples of a continental-oceanic plate collision are the collision between the Nazca Plate (Oceanic plate) and South American Plate (Continental Plate) forming the Andes Mountains, many volcanoes also, and Peru-Chile Trench. Another example is the formation of Rocky Mountains by collision of Juan-De-Fuca (Oceanic plate) and North American Plate (Continental plate), forming volcanoes like Mt. Shasta.

Question 11

What are the features formed in the collision between Oceanic-Oceanic plates?

Answer 11

The features formed in the collision between Oceanic-Oceanic plates are volcanoes or volcanic islands, trenches, and earthquakes.

Question 12

Why don’t Fold Mountains form in the collision between Oceanic-Oceanic plates?

Answer 12

Fold Mountains do not form in the collision between Oceanic-Oceanic plates because both plates are Basaltic Plates. The heavier basaltic plate subducts but is not able to uplift the other basaltic plate.

Question 13

What is the reason behind the formation of trenches in the collision between Oceanic-Oceanic plates?

Answer 13

In the collision between Oceanic-Oceanic plates, the similar types of plates result in trenches forming. In fact, the deepest trenches form in Oceanic-Oceanic plate collisions.

Question 14

What is an example of a trench formed in the collision between Oceanic-Oceanic plates?

Answer 14

An example of a trench formed in the collision between Oceanic-Oceanic plates is the Mariana Trench.

Question 15

What do volcanic eruptions at Oceanic-Oceanic plate collisions form?

Answer 15

Volcanic eruptions at Oceanic-Oceanic plate collisions form Seamounts and Volcanic islands.

Question 16

What are the features formed in the collision between Continental-Continental plates?

Answer 16

The features formed in the collision between Continental-Continental plates are Fold Mountains, earthquakes, and foredeeds.

Question 17

Why don’t volcanic eruptions occur in the collision between Continental-Continental plates?

Answer 17

Volcanic eruptions do not occur in the collision between Continental-Continental plates because no subduction takes place due to the much lesser density of the continental plates compared to the Asthenosphere.

Question 18

Why don’t trenches form in the collision between Continental-Continental plates?

Answer 18

Trenches do not form in the collision between Continental-Continental plates because there is no subduction due to the much lesser density of the continental plates compared to the Asthenosphere.

Question 19

What causes earthquakes in the collision between Continental-Continental plates?

Answer 19

Earthquakes occur in the collision between Continental-Continental plates due to friction between the two plates.

Question 20

What is the reason for no subduction in the collision between Continental-Continental plates?

Answer 20

No subduction takes place in the collision between Continental-Continental plates because the continental plates have much lesser density than the Asthenosphere.

Question 21

What is the significance of Foredeed in the formation of mountains?

Answer 21

Foredeed refers to the overlapping of rock layers that occur during the formation of Fold Mountains. It is significant because it creates a stronger and more stable structure of the mountain.

Question 22

What is the main difference between the collision of Continental-Continental Plate and Oceanic-Oceanic Plate?

Answer 22

The main difference between the collision of Continental-Continental Plate and Oceanic-Oceanic Plate is that in the former case, Fold Mountains are formed while in the latter case, they do not form due to the similar types of plates.